Agitating apparatus



July 31, 1951 R. M. GOGOLICK ETAL 2,562,545

AGITATING APPARATUS Filed June 9, 1949 3 Sheets-Shet 1 July 31, 1951 R.M. GOGOLICK ETAL 2,562,545

AGITATING APPARATUS Filed June 9, 1949 3 Sheets-Sheet 2 July 31, 1951 R.M. GOGOLICK ETAL 2,562,545

AGITATING APPARATUS Filed June 9, 1949 3 Sheets-Sheet 5 Patented July31, 1951 UNITED STATES PATENT OFFICE North Billerica, Mass., assignorsto Ultrasonic Corporation, Cambridge, Mass, a, corporation ofMassachusetts Application June 9, 1949, Serial No. 98,011

9 Claims. 1

Our invention relates to apparatus for agitating materials to changetheir condition or character. In particular, the invention comprisesapparatus for generating compression waves (sonic energy) in a longnarrow beam well adapted to operate with uniform effect across movingsheets, webs or material riding on a conveyor.

Others have recognized phenomena resulting from the subjection ofvarious materials to compression wave agitation. For example, sonicenergy has been known to effect the homogenization of milk, the killingof bacteria, emulsification of liquids, the flocculation anddeflocculation of solid particles, and rapid dyeing of textiles.Difiiculties attendant upon the generation of sonic energy in liquidshas led to the development of apparatus for generating compression wavesin a gaseous medium and applying the waves to the materials undergoingtreatment. However, conventional sound generators of the siren typeproduce conical beams which decrease in intensity as the distance fromthe center increases.

The most important object of our invention is to produce sound waves ofuniform intensity throughout a narrow linear zone and thereby make itpossible to subject a moving band of material to compression waveagitation having identical effect throughout the width of the band.

Another object of the invention is to provide a compression wavegenerating and radiating system applicable for the establishment of along narrow sound field of high intensity.

An important feature of the invention resides in the combination of along flat slotted stator coupled at one side to an acoustic horn havinga long narrow mouth, and provided on the other sidewith a shuttercontrolling the stator slots; Means are also provided for supplyingfluid under pressure to the shutter-stator combination.

Another feature of the invention comprises a resonant chamber coupled tothe acoustic horn andgfurnished with means for the continuous passage ofmaterial through the chamber.

These and other objects and features of the invention will be bestunderstood and appreciated from the following description of a preferredembodiment thereof selected for purposes of iilustration and shown inthe accompanying drawings in which: a

Fig. 1 is a view in side elevation of agitating apparatus constructed inaccordance with the invention,

Fig. 2 is a view in cross-section along the line 2-2 of Fig. '1, I

Fig. 3 is a view in end elevation of the apparatus, portions thereofappearing in cross section,

Fig. 4 is a view in cross section on an enlarged scale showing therelation of the stator, the endless belt, and the horn,

Fig. 5 is a plan view of a portion of the endless belt,

2 Fig. 6 is a plan view of an alternative form of belt, V Fig. 7 is aplan view, much enlarged, of a portion of the stator,

Fig. 8 is a view in cross-section along the line 8--8 of Fig. 7,

Fig. 9 is a plan view of the stator and bed plates,

Fig. 10 is a view in cross section along the line Ill-Ill of Fig. 9, andI Fig. 11 is a view in end elevation of the apparatus as coupled to aresonant chamber and material conveyor.

In the particular embodiment of our invention shown in the drawings weorganize the compression wave producing apparatus about an opposed pairof heavy hollow iron side frames I0 and I2 disposed in parallel relationand each closed at its ends by a pair of plates 14 to define, in effect,a long, narrow rectangular box structure open at the top and bottom.Secured to the inside of each side frame by screws 22 is a long hollowcasting having a flat top iii, a curved inner face 20, and a thickenedbase 2| merging smoothly into the curving side. The two castingstogether form a long flat bed I8 and an exponential acoustic horn 20having a long narrow mouth running the length of the bed plate, the hornbeing closed at its ends by the plates I 4.

Each plate I8 is recessed adjacent the mouth of the horn to receivemembers comprising a stator. One member 24 consists of a longrectangular metal strip milled along one margin to produce a series ofteeth 23 forming a series of uniformly spaced rectangular slots, clearlyshown in Fig. '7. The strip 24 is also, provided with a series ofcounterbored screw holes 25 by means of which it is held fiat upon theplate I8 by a number of screws 26. Adjacent the roots of the teeth 23are three parallel grooves 21 running throughout the length of themember 24 to form a labyrinth seal as will hereafter be discussed. Themember 24 is so placed on the plate l8 that the alternate teeth andslots overlie the mouth of the horn 20.

The second stator piece consists simply of a flat strip 28 held on theplate l8 in abutting re-'- lation with the member 24 by means of aseries of screws 30. The two pieces 24 and 28 may thus be regarded as along flat member having a series of uniformly spaced slots or aperturescommunicating with the mouth of the horn 20. t A

Secured to the bed plates is over the stator is a hood or box 36provided with a base flange 40 receiving a plurality of bolts forholding the hood in position. The hood 36 is fluid tight except for thestator, which in eifect serves as a portion of a wall of the hood; 9.rubber hose 38 is secured to an appropriate fitting 39 formed in thehood 35 and serves to supply air or other fluid to the hood, the latterbeing employed as a pressure chamber from which fluid is periodi-r callydischarged through the slotted stator.

3 The bottom wallof the hand 36 is provided with a narrow longitudinalslot '43 overlying' the slotted stator; the bottom wall is also recessedadjacent the slot to receive an opposed pair of guide strips 44 eachprovided with an'upwardly offset overhanging inner margin. Thestrips.

are secured to the bottom ofthehood. 3'6.;by-means.

of a series of screws 46.

At one end of the side frame In therezisiseacured a vertical standard46, while a similar standard 48 is mounted at the opposite end- At. thetop of the standard 46 there is secured a.v

yoked bearing member50 in which is journ-aled a stub shaft 52 carrying apulley 56 at one end amt'aslarge =wh'eel :54 at 'theoth'er end. A V-belt'58 is looped over the pulley 56 and driven by'a motor (notshown)...

A heavy bracket 60 is secured'to the standard Thy a pair 'of fb'o'ltsfitworking in an elongated slot 6| cut in the side of the bracket which isoutwardly fianged'at its bottom to'receive an adjmted bolt fl' which"bears on the base ofthe standard 48. The top of the'bracket 60 'is alsooutwardly flanged toxprovide support for an'opoftguiderrails 66 betweenwhich slides a carriage '68 carrying a yoked bearing housing'"IllfW-fiiCh a stub shaft 12'is:journaled. An adjusting 'bolt:lkworkstin a lug 16 mounted on the sider'ofi the bracket and operatesto slide the car'- riageifii horizontally; AlargewheellB is fiired toonevend 'Qflthestu-b shaft "and may be .adjustedhorizontally andvertically by 'manipula ti'ontof the-bolts 6 I and '14;-

Artendlesststeel belt80', similar'to aband saw blade; is. loopedioverthewheels 54' and 18; its bottomirun being substantially straight'andpassing overitheislotted stator members and 28 and beneath thegu-i'des44-which serve as=edgeguides keepingthe belticonfined to a linear path.The tension--oftthe' belt may be adjusted by moving theiwheelilrbodily'by means of thebolts 64'and 14.

The belt "Bo is provided throughout its length with". a: plurality ofuniformly spacedslots corresponding to but slightly smaller than theslots in:the stator;' 'I'heslots'82'; as shown,arerectangulanxalth'ough' circles; ellipses, etc. may'be employedias?suggested at" 82" in' Fig; 6. Stator openings; of similar"- geometry mayalso be employed.

When the wheel 54'is driven, the'b'elt fill-slides across the flat"stator members 24 and 28 and thusmlternatelyopens and closes'the slotsin the stator: Ihxeflect; the belt servesas a shutter; wherrrth'e belt'slots 82 are registered with the slots :in the-stator, air or otherfiuidin' the hood llzisodischarged' through the belt slots; the statorslots, and into the long acoustic horn 20$ The intensity'of the sound'waves generated depends uponthe-ipressure of the fluid'forced into thehood 3i; whilefth'e frequency is a function of the speed at.which'thebelt'is driven. Itis extremely important that 'the'slots inthestator'andin the belt be-iuniformly spaced in'both instances, sinceotherwise. some of 'the stator slotswillbe open while. others:are'closed or partially closed; The resultthenistthat fiuid'iscontinuously discharged from'theahoodfrather than emittedonly in shortbursts; Inasmuch1as=the intensity of the waves generated-by'theapparatus is a function of the fiuid. pressure-in the hood, it followsthat the hood; mustb'eairtight and fitted in airtight sealingrelation'uponthe'bed plates l8. Leakage'of fiuidistminimizedby theposition of the grooves 2T=whichitform, in effect, a labyrinth sealwhich .4 tends toeliminate the lateral emission of fluid. It'shouldfurther be pointed out that the pressurized fiuid bears against theinner surface of the belt and tends to hold it against the upper surfaceof the stator, thereby further reducing: leakage.

Apparatusofithe type shown may be used to generatecompression waves atfrequencies at 1east'as':high.as 5',000 cycles per second and ataniintensitypf "at' least 160 db. (better than a sound pressure. of 10dynes per square centimeter).

Sonic'energy of these proportions may effectively be used for manyindustrial purposes. For example; in'th'e' manufacture of paper the wetpulp' is-spreadupon a traveling screen conveyor where it=is dried." Ithas long been recognized that "the fibersof the pulp'tend tolie'parallel to each other with the result that the finished paper 'ismuch' less'resistant to shearing, stresses in one direction than inanother; Various attempts have been made to' deflocculate or disorientthe pulp fibers 'so'thatthey will lie completely at random. We "havefound that sound 'waves may be employed" for this'purpose with aconsiderable dgreeof success; However, conventional sources ofsoundwaves are not'suitable because the intensity varies radically from pointto point in the-sound field; Apparatus of the typeherein shown, however,is distinguished for the production of a long narrow sound field andthus lends itself admirably to the treatment of paper pulp.

In Fig'. 11 there is shown; somewhat diagrammatically; anarrangement inwhich the compression wave-agitator of our invention ma usefully beapplied" for the defiocculation' of paper pulp fibers. A long narrowrectangular chamber is formed by'metal sheets 84 bolted to the sideframes= I II and H of the generating apparatus and'bysuitable-endwalls85. The apparatus with the-chamber beneath it is poised transverselyover a conveyor belt 86 passing over a driven roller88: The'paper pulp90 is carried on the belt across the-bottom of the chamber and thussubjected to'the compression' waves radiated by the acoustic horn 20. Asbefore stated, the sound waves act'to shake the'fibers'of' the paperpulp anddistribute themat random so that whenthe pulp has-dried;theresulting paper willbe uniformly'strong m'all directions.

In'desi'gning the hood and the treating-chemb'er" it is important'tochoose dimensions which will minimize-out ofphase reflections; That isto 'say'if a'soundwave refiected from the pulp, on theb'elt 86 returnsto the interface of the stator and'belt slots inproper phase'relation,the second refiecti'on'willtend' to augment the newly gener ated wave.If'the phase is displaced, the returning wavewill tend to buckand'diminish the wave being'generated. Similarly every time a wave ispropagated through the horn 20 another wave is propagated'backup intothe hood. Consequently it "is' desirable so to design the hood that backrefiected waves will return to the stator in proper phase relation.Naturally, the frequency at which the apparatus is to be operated willlargely determine the selection of the proper dimensions. In generalitmay be stated that the distance from the interface or upper surfaceof'the stator, to the refi'ecting surface should be'an uneven multipleof a quarter wavelength.

To give an example of a unit constructed in accordance with theinvention and which has been successfully operated, a belt'208.l.' longis provided with 1664' slots, each .051 wide and 3 2'" long. Theeffective length of the stator was 30" and it was provided with 240slots each .059" Wide and FA" long. The practical upper limit of thefrequency of the waves generated is about 15 kc.. but this may begreatly increased by using a double stator and two endless belts drivenin opposite directions. It is to be emphasized that these figures are byno means critical and are inserted here merely to give an idea of theorder of magnitude of a satisfactory device constructed in accordancewith the invention.

Although an endless belt has been shown as the element controlling theopening and shutting of the stator ports, the invention is not limitedto an embodiment in this form. For example, a reciprocating strip orshutter provided with suitable slo'ts may be mounted above the statorand used to generate sound waves. It will be found in practice that thereciprocating shutter is less desirable for the generation of waves atrelatively high frequencies, since the rate of reciprocation becomesimpractically great. For relatively low frequencies the reciprocatinggate or shutter may well offer advantages. Those skilled in the art willreadily appreciate the possibility of wide variations in the design ofthe unit, but the scope of the invention is to be measured in terms ofthe appended claims rather than in the detailed description above.

Having thus disclosed our invention what we claim as new and desire tosecure by Letters Patent of the United States is:

1. Apparatus for agitating materials with compression waves comprising apair of wheels mounted for rotation on spaced parallel axes, means fordriving one of said wheels, an endless belt looped over said wheels andhaving one run disposed along a straight path, said belt being providedthroughout its length with uniformly spaced apertures, an elongated bedplate disposed beneath the straight run of said belt, opposed guidesdisposed to engage said belt and confine it to close juxtaposition withsaid bed plate, said bed plate having a plurality of uniformly spacedapertures disposed in a line parallel to said belt in position to beopened and closed as said apertured belt passes over the bed plate, anacoustic horn communicating with the side of the bed plate opposite thebelt, and walls forming a resonant chamber communicating with said horn.

2. Apparatus for agitating materials with compression waves, comprisinga long substantially fiat member provided with a series of aligneduniiormly spaced apertures extending along the long dimension of saidmember, an endless belt provided with a series of aligned uniformlyspaced apertures, means for driving the belt through a path including asection in close proximity to and in parallel relationship with saidmember and with the direction of said series of apertures, and wallsforming a chamber communicating with said belt and member, whereby fluidmay be introduced to said chamber under pressure and dischargedtherefrom in repeated bursts as the movement of the belt alternatelyopens and interrupts the apertures in said member.

3. Apparatus for agitating materials with compression waves, comprisingan endless belt provided wtih a series of apertures, an elongated memberalso provided with a series of apertures extending longitudinally alongsaid member, means for driving the belt through a path including asection in close proximity to and in parallel relationship with themember and to the direction of said series of apertures, and means forsupplying fluid under pressure to an area overlying said belt andmember.

4-. Apparatus for agitating materials with compression waves, comprisingwalls forming a chamber, a substantially flat elongated member servingas a portion of a wall of said chamber and provided with a plurality ofaligned apertures, an endless belt provided with a plurality of alignedapertures, and means mounting said belt for movement through a pathtraversing said chamber in close juxtaposition to and in parallelrelationship with said member and with the direction of alignment ofsaid series of apertures, whereby the apertures of said member arealternately closed and opened by said belt to generate a band ofcompression waves.

5. Apparatus for agitating materials with compression waves, comprisingan elongated substantially fiat member provided with a plurality ofaligned apertures, walls forming a chamber including said member as partof a wall, and a shutter mounted for movement in close proximity to andin a path parallel to said apertures in position alternately to open andclose said apertures, thereby forming agitating compression waves.

6. Apparatus for agitating materials with compression waves comprisingwalls forming a chamber, a flat elongated member forming a portion ofone of said walls and provided with a series of aligned apertures, along shutter disposed in close proximity to said member in positionalternately to open and close said apertures, said elongated memberbeing parallel to the direction of movement of the shutter and means foradmitting fluid under pressure to said chamber.

7. Apparatus for agitating materials by compression waves comprisingwalls forming a chamber, a long fiat member serving as a portion of oneof said walls and provided with a plurality of uniformly spaced alignedapertures, an endless belt having a plurality of aligned apertures andmounted for movement along a path parallel to said member and to thedirection of alignment of said apertures including a section in closejuxtaposition to said member, and an acoustic horn having a long narrowmouth coupled to said member on the side opposite said chamber.

8. The structure defined in claim 7 wherein are provided walls forming aresonant chamber coupled to said horn.

9. Apparatus for agitating materials by compression waves, comprising aconveyor belt, a. narrow elongated acoustic horn mounted transverselyabove said belt, said horn having a long narrow mouth, a long flatapertured stator, and a long shutter, said stator and shutter beingmounted at the mouth of the horn in operative combination, said statorand shutter bein parallel with the long mouth of the horn and wallsforming a pressure chamber communicating with.

said horn through said stator and shutter combination.

ROLAND M. GOGOLICK. CHANDLER L. GOLDTHWAITE. W. F. PRESTON PARDY.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 973,391 Severy Oct. 18, 19101,794,190 Loman Feb. 24;, 1931

